It is known to treat abnormal tissue, such as cancerous tumors, using radiation therapy. During radiation therapy, the targeted biological tissue is selectively exposed to therapeutic doses of radiation, preferably in a manner whereby the target tissue is killed, while sparing surrounding healthy tissue. Recently, it has been discovered that the use of hyperthermia (HT) therapy can be used as an adjunct to standard radiation therapy to increase the efficacy of the treatment. Hyperthermia can be defined as the treatment of disease by raising body temperature. Hyperthermia for the treatment of cancer involves the use of heating devices, such as microwave applicators, ultrasound, low energy radio frequency conduction probes, or a sophisticated thermometry system of micro-thermocouples placed externally, interstitially, or in the natural cavities of the body to make cancerous tumors more operable, radiosensitive, or susceptible to cancer therapy measures. Hyperthermia can be applied prior to, during, and/or subsequent to the radiation therapy.
According to a study published in the May 1, 2005 edition of the Journal of Clinical Oncology, patients with post-mastectomy chest wall recurrence of breast cancer who were given HT therapy experienced complete response (total disappearance of the tumor) at a rate nearly three times higher than those patients who received radiation treatment alone. The use of adjuvant hyperthermia also demonstrated a significant improvement in tumor control, among patients with recurrent melanoma as well as head and neck and other tumors when compared to stand-alone radiation therapy. It is thought that when combined with radiation therapy, hyperthermia creates a mechanism that interferes with the cellular repair of radiation-induced DNA damage.
During a radiation treatment session, the position and movement of the target tissue can be monitored by an imaging system, such as a fluoroscopic imaging device, magnetic resonant imaging (MRI) device, computed tomography (CT) device, or positron emission tomography (PET) device. The radiation beam can then be adjusted to ensure that the target tissue is in a desired position while the radiation is being delivered. Tracking of the target tissue can be accomplished using artificially placed internal markers as reference points. While generally successful, however, this tracking technique requires the additional step of placing the markers within the patient's body.
Thus, there remains a need to provide an improved system and method capable of applying radiation/HT therapy to a target tissue region, while tracking the position and/or movement of the target tissue region to facilitate focused treatment of the target tissue region.